JP2024074332A - sewing machine - Google Patents

Abstract

[Problem] To feed the sewn material well. [Solution] The sewing machine includes a feed mechanism 20 that feeds the sewn material from below a needle plate 101 using conveyor belts 21-24, and a presser mechanism 70 that presses down the sewn material fed by the conveyor belts 21-24 from above. Each conveyor belt may be configured to contact the sewn material around the needle drop position, for example, either the front, rear, left or right, or the rear and left side, front and left side, front and right side, or rear and right side in the feed direction. In this case, each conveyor belt may be configured to use multiple motors as a drive source for conveyance, and to include a control device that individually controls the conveyance speed of each motor. [Selected Figure] Figure 2

Description

The present invention relates to a sewing machine that sews while feeding the workpiece with a feed mechanism.

Conventional sewing machines press the workpiece from above with a presser foot on the upper surface of the needle plate, and sew while feeding the workpiece at a specified stitch pitch from below the needle plate with a feed dog (see, for example, Patent Document 1).

JP 2010-246839 A

In a conventional sewing machine, a feed dog makes a circular movement below the needle plate, and the tip of the feed dog comes into contact with the underside of the workpiece at the upper part of the orbital movement path, thereby feeding the workpiece.
As a result, the tips of the feed dogs come into contact with the workpiece, which is held down from above by the presser foot, as if striking it from below, during the feeding operation, causing vibrations in the workpiece.
In particular, when the sewing machine rotates at high speed, the tips of the feed dogs strike the workpiece hard, causing vibrations that can bounce the workpiece up, resulting in large errors in the stitch pitch.
In addition, since the feed dog reciprocates in the feed direction due to its circular motion, the inertial force in the feed direction increases as the feed dog rotates at a higher speed, which causes errors in the stitch pitch.

The purpose of the present invention is to provide good feeding of the sewing material.

The present invention relates to a sewing machine,
a feed mechanism that feeds the workpiece from below the needle plate by a conveyor belt;
and a presser mechanism that presses down the workpiece fed by the conveyor belt from above.

According to the present invention, since the feed mechanism feeds the workpiece by the conveyor belt below the needle plate, it is possible to suppress vibrations caused by the workpiece being struck from below.
Furthermore, unlike the case where the feed dog and its peripheral members rotate, the inertial force of the conveyor belt can be reduced.
Furthermore, since the presser mechanism presses the workpiece from above, the workpiece can be brought into close contact with the conveyor belt, and the workpiece can be made to smoothly follow the feeding operation of the conveyor belt.
As a result, the sewing material can be fed with greater precision.
Furthermore, since there is no need for a feed dog that moves back and forth in the horizontal direction and a feed mechanism that imparts this movement to the feed dog, noise can be reduced as a result of the reduction in vibration.

1 is a front view of a sewing machine according to an embodiment of the present invention; FIG. FIG. FIG. 2 is a perspective view showing the top surface of the left end portion of the sewing machine bed. FIG. 4 is a perspective view showing the top surface of the left end portion of the bed of the sewing machine with the presser foot not shown. 4 is a front view of a cloth presser mechanism that presses down an object to be sewn on the needle plate from above; FIG. FIG. 4 is a perspective view of a guide frame of the feed mechanism. FIG. 2 is a perspective view of a feed mechanism in which four conveyor belts are in a front-rear differential feed state. 1 is a perspective view of a feed mechanism in which four conveyor belts are in a left-right differential feed state; FIG. 2 is a block diagram showing a control system of the sewing machine. 13 is an explanatory diagram showing, in a plan view, another example in which the conveyor belt contacts the sewing workpiece at a different position relative to the needle hole to convey the sewing workpiece; FIG. 13 is an explanatory diagram showing, in a plan view, another example in which the conveyor belt contacts the sewing workpiece at a different position relative to the needle hole to convey the sewing workpiece; FIG. 13 is an explanatory diagram showing, in a plan view, another example in which the conveyor belt contacts the sewing workpiece at a different position relative to the needle hole to convey the sewing workpiece; FIG.

[Overall configuration of the embodiment]
A sewing machine according to an embodiment of the present invention will be described in detail below.
FIG. 1 is a front view of the sewing machine 100, FIG. 2 is a perspective view of the sewing machine 100, and FIG.
Hereinafter, the downstream side in the feed direction of the workpiece will be referred to as the "front", the upstream side in the feed direction will be referred to as the "rear", the left hand side when facing forward will be referred to as the "left", the right hand side will be referred to as the "right", the vertically upward will be referred to as the "upper", and the vertically downward will be referred to as the "lower". The front-to-rear, left-to-right, and up-to-down directions are perpendicular to one another.
In the following description, it is assumed that the sewing machine 100 is placed on a horizontal surface, and the front-to-back and left-to-right directions are horizontal.

As an example of a sewing machine 100 according to an embodiment of the present invention, a so-called lock stitch sewing machine is shown.
The sewing machine 100 includes a sewing machine frame 110, a needle up-down movement mechanism, a feed mechanism 20, a presser foot mechanism 70, a shuttle mechanism, and a control device 90.
The sewing machine 100 is equipped with various components such as a thread take-up mechanism and thread tensioner that are equipped in a typical lock stitch sewing machine, but as these are well known, a description thereof will be omitted.

[Sewing machine frame]
The sewing machine frame 110 supports or houses each component of the sewing machine 100 described above.
The sewing machine frame 110 has a sewing machine bed portion 111 , a vertical body portion 112 , and a sewing machine arm portion 113 .
The sewing machine bed portion 111 is located at the bottom of the sewing machine 100 and extends in the left-right direction.
The upright body portion 112 stands upright from the right end portion of the sewing machine bed portion 111 .
The sewing machine arm portion 113 extends leftward from the upper end portion of the upright body portion 112 .
The sewing machine bed 111 has a lower cover 114 (see FIG. 6) that covers the bottom side thereof, but this is not shown in FIGS. 1 to 3.

[Needle up/down movement mechanism]
FIG. 4 is a perspective view showing the upper surface of the left end of the sewing machine bed portion 111, and FIG. 5 is a perspective view showing the upper surface of the left end of the sewing machine bed portion 111 without illustration of a presser foot, which will be described later.
The needle up-down movement mechanism, as shown in FIGS. 1 to 5, is disposed inside the sewing machine arm portion 113, is rotated by the sewing machine motor 16 (see FIG. 10), and has an upper shaft along the left-right direction.
The needle up-down movement mechanism further comprises a needle bar 12 which holds the sewing needle 11 at its lower end, and a crank mechanism which converts the rotational force of the upper shaft into a reciprocating driving force for up-down movement and transmits it to the needle bar.
Incidentally, the upper shaft and the crank mechanism are not shown in the figure since they are well known.

The needle bar 12 extends in the vertical direction and is supported at the lower left end of the sewing machine arm portion 113 so as to be movable up and down.
The sewing needle 11 moves up and down together with the needle bar 12. A needle plate 101 made of a horizontal flat plate is provided below the needle bar 12 on the upper surface of the sewing machine bed portion 111.

A composite opening 102 is formed at the needle drop position of the sewing needle 11 relative to the needle plate 101. In the composite opening 102 of the needle plate 101, a pinhole member 30 having a pinhole 13 and the first to fourth conveyor belts 21 to 24 of the feed mechanism 20 described below are arranged so as to be exposed upward. In other words, the composite opening 102 has a shape in which a rectangular opening in which the pinhole member 30 and the first to fourth conveyor belts 21 to 24 are exposed are integrally combined.

[Kettle mechanism]
As shown in FIGS. 2 and 3, the shuttle mechanism has an outer shuttle 14 and an inner shuttle 15 provided below the needle hole member 30 of the needle plate 101, and a shuttle shaft (not shown) for rotating the inner shuttle 15.
The shuttle shaft is supported rotatably along the left-right direction within the sewing machine bed portion 111. The shuttle shaft receives rotation about its axis along the left-right direction, which is twice as fast as the rotation of the upper shaft described above, via a gear mechanism or a belt mechanism.

The inner hook is housed inside the outer hook. The inner hook further houses a bobbin (not shown) for supplying a lower thread.
The outer hook is connected to the left end of the hook shaft and rotates around the inner hook. The inner hook is restricted from rotating together with the outer hook. The outer hook has a point on the outer periphery for capturing the loop of the upper thread from the sewing needle 11. When the outer hook rotates, the point captures the loop of the upper thread and allows the bobbin thread that is being paid out from inside the inner hook to pass through it.
The outer hook and the inner hook are arranged in a housed state inside a substantially cylindrical guide frame 29 of the feed mechanism 20, which will be described later.

[Fabric pressing mechanism]
FIG. 6 is a front view of the presser mechanism 70 which serves as a presser mechanism for pressing down the workpiece on the needle plate 101 from above.
The fabric presser mechanism 70 includes a presser foot 71 , a presser bar 72 , a presser motor 73 , a transmission mechanism 74 , a presser spring 75 , and a presser height detection unit 76 .

The presser foot 71 is disposed above the composite opening 102 of the needle plate 101. The presser foot 71 presses down the workpiece fed by the feed mechanism 20 from above, and appropriately transmits the conveying forces of the first to fourth conveyor belts 21 to 24 to the workpiece.
As shown in FIG. 4 , the presser foot 71 has a bottom plate 711 that presses down on the workpiece from above, and a connecting portion 712 that is attached to the lower end of the presser bar 72 .

The bottom plate 711 has a smooth bottom surface and an upstream side (rear end) in the cloth feeding direction that is curved upward to present a so-called boat shape.
The connecting part 712 is erected on the upper surface of the front end part of the bottom plate 711 and is connected to the bottom plate 711 so as to be able to swing somewhat around an axis along the left-right direction. The upper end part of the connecting part 712 can be detachably connected to the lower end part of the pressing bar 72 by means of an attachment screw.
A plurality of presser feet 71 having different shapes, dimensions or structures may be prepared according to the type of sewing or the type of material to be sewn, and may be appropriately replaced as required.

The presser bar 72 is located immediately in front of the needle bar 12 and is supported inside the sewing machine arm 113 in a vertically aligned state. The presser bar 72 is supported so that it can move up and down by metal bearings 721, 721 arranged vertically inside the sewing machine arm 113.

The upper end of the presser bar 72 protrudes upward from the upper surface of the sewing machine arm portion 113 and is equipped with a knob member 724 for being grasped by hand to pull up the presser foot 71 .
Between the upper and lower metal bearings 721 of the pressing bar 72, an upper bar holder 722 and a lower bar holder 723 are fixedly attached by being clamped.

A sleeve 725 that is vertically slidable relative to the pressing bar 72 is provided below the upper bar holder 722. A coil-shaped pressing spring 75 is provided between the sleeve 725 and the lower bar holder 723.
The vertical distance between the upper bar holder 722 and the lower bar holder 723 is set narrower than the total length of the natural length of the pressing spring 75 and the sleeve 725. Therefore, the pressing spring 75 is always compressed and presses the pressing bar 72 downward via the lower bar holder 723.

The presser motor 73 is a motor whose amount of movement can be arbitrarily controlled, such as a stepping motor, and functions as a drive source for raising and lowering the presser foot 71 and for adjusting the presser pressure.
The presser motor 73 is supported by a plate-shaped bracket 731 at the upper inside portion of the upright body portion 112 with its output shaft facing rearward.
An encoder 732 is connected to the output shaft of the presser motor 73 (see FIG. 10). The shaft angle of the output shaft detected by the encoder 732 is input to the control device 90.

The transmission mechanism 74 has a function of transmitting the lifting and lowering motion to the presser bar 72 using the presser motor 73 as a drive source.
The transmission mechanism 74 has a driving gear 741 , a substantially sector-shaped driven gear 742 , a link member 745 having bifurcated rotating arms 746 , 747 , and a connecting rod 749 .

The main gear 741 is mounted on the output shaft of the presser motor 73. The main gear 741 and the driven gear 742 are spur gears, and are in mesh with each other.
The driven gear 742 is supported rotatably about an axis along the front-rear direction within the sewing machine frame 110. An arm portion 743 extending radially outward of the driven gear 742 is connected to one end of a connecting rod 749 rotatably about an axis along the front-rear direction.

The link member 745 is supported rotatably about an axis along the front-rear direction within the sewing machine arm portion 113. One rotating arm 746 of the link member 745 is connected to the other end of a connecting rod 749 so as to be rotatable about an axis along the front-rear direction. The other rotating arm 747 of the link member 745 is connected to the sleeve 725 via a square piece (not shown).
The square piece is connected to the rotating arm 747 so as to be rotatable about an axis along the front-rear direction. Furthermore, the square piece is supported on the sleeve 725 so as to be slidable along the left-right direction.
Therefore, when a rotational movement is applied to the link member 745, the square piece slides in the left-right direction, and the sleeve 725 can be caused to move up and down.

6, the sleeve 725 is raised via the driving gear 741, the driven gear 742, the connecting rod 749, the link member 745, and the square piece. When the presser motor 73 is driven in the counterclockwise direction, the sleeve 725 is lowered.
Therefore, when the presser foot 71 has not yet reached the upper surface of the needle plate 101, the presser foot 71 can be raised and lowered by the rotational drive of the presser motor 73.
Furthermore, when the presser motor 73 is driven counterclockwise with the presser foot 71 reaching the upper surface of the needle plate 101, the presser spring 75 is compressed to increase the pressing pressure of the presser foot 71.
Furthermore, when the presser foot 71 reaches the upper surface of the needle plate 101 and the presser motor 73 is driven clockwise, the presser spring 75 is extended to reduce the pressure of the presser foot 71. This makes it possible to adjust the pressure of the presser foot 71 against the material being sewn.
Therefore, the presser motor 73, the transmission mechanism 74 and the presser spring 75 function as an adjustment mechanism for adjusting the presser pressure on the material to be sewn.

The presser height detection unit 76 detects the height of the presser foot 71. The presser height detection unit 76 is composed of a detection target 761 supported by the lower bar support 723 and a height sensor 762 such as a line sensor that optically detects the height of the detection target 761.
The object to be detected 761 is supported by the lower bar support 723 and therefore moves up and down together with the presser foot 71 and the presser bar 72 .
The height sensor 762 is fixed inside the sewing machine arm portion 113, and has light receiving elements aligned along the Z-axis direction. The height sensor 762 is shielded by the detection object 761, and can detect the position (height) in the Z-axis direction of the upper end of the detection object 761, thereby detecting the height of the presser foot 71.

For example, while the presser foot motor 73 is driven in the downward direction of the presser foot 71, the height of the presser foot 71 is monitored by the height sensor 762. Then, when the presser foot 71 comes into contact with the workpiece on the needle plate 101 and the downward movement of the presser foot 71 stops, the stop can be detected by the height sensor 762. Furthermore, the amount of rotation of the presser motor 73 in the downward direction from when the downward movement of the presser foot 71 stops can be detected by the encoder 732, so that the presser pressure of the presser foot 71 can be obtained.
In other words, by controlling the amount of rotation of the presser motor 73 based on the detection of the height sensor 762 and the encoder 732, the pressing pressure of the presser foot 71 can be adjusted as desired.

In the above example, the detectable object 761 is provided on the lower bar support 723, but the detectable object 761 can be provided on any part of the pressing bar 72 as long as it rises and falls together with the pressing bar 72.

[Feed mechanism]
Fig. 7 is a perspective view of a guide frame 29 of the feed mechanism 20, and Figs. 8 and 9 are perspective views of the feed mechanism 20. Figs. 8 and 9 show different stretching states of first to fourth conveyor belts 21 to 24, which will be described later.
The first to fourth transport belts 21, 22, 23, and 24 may be collectively referred to as belts 21 to 24.
The feed mechanism 20 will be described in detail below with reference to FIGS. 1 to 5 and 7 to 9.

As shown in each drawing, the feed mechanism 20 includes belts 21 to 24, a first motor 25, a second motor 26, rotating shafts 27 and 28, a first pulley 31, and a second pulley 32.
The feed mechanism 20 further includes a guide frame 29 for guiding the belts 21 to 24 so that they come into contact with the lower surface of the workpiece, a first pressure mechanism 33, and a second pressure mechanism .

The first and second motors 25, 26 are each a motor whose operation amount can be arbitrarily controlled, such as a stepping motor. The first and second motors 25, 26 are arranged in a line up in front and behind each other, inside the right end portion of the sewing machine bed portion 111, and have their output shafts facing leftward.
A first pulley 31 is connected to the output shaft of the first motor 25 on the front side via a rotating shaft 27 .
A second pulley 32 is connected to the output shaft of the second motor 26 on the rear side via a rotating shaft 28 .

The rotary shafts 27 and 28 are both parallel to each other in the left-right direction and are rotatably supported within the sewing machine bed portion 111 .
The first and second pulleys 31, 32 are supported rotatably around axes extending in the left-right direction within the left end portion of the sewing machine bed portion 111. Rotational motion is imparted to the first and second pulleys 31, 32 by the first motor 25 and the second motor 26 via the rotary shafts 27, 28, respectively.
The first and second pulleys 31, 32 are arranged to overlap each other when viewed from the front-rear direction, i.e., they are at the same height and in the same position in the left-right direction.

The first and second pulleys 31 and 32 are each capable of stretching all of the first to fourth conveyor belts 21, 22, 23, and 24 that are arranged in parallel in the left-right direction.
That is, the first pulley 31 has, on its outer circumferential surface, a left groove 311 for passing the first and second transport belts 21, 22 therethrough and a right groove 312 for passing the third and fourth transport belts 23, 24 therethrough.
The second pulley 32 has, on its outer circumferential surface, a left groove 321 through which the first and second transport belts 21, 22 are passed and a right groove 322 through which the third and fourth transport belts 23, 24 are passed.
Each of the belts 21 to 24 has the same width, and each of the left and right grooves 311, 312, 321, 322 has a width of at least two belts.
This allows each of the belts 21 to 24 to be stretched over the first pulley 31 and the second pulley 32 as appropriate.

The first to fourth conveyor belts 21 , 22 , 23 , 24 are endless circular belts, and are stretched between a guide frame 29 and a first pulley 31 or between the guide frame 29 and a second pulley 32 .
The first to fourth transport belts 21, 22, 23, and 24 are arranged in parallel in order from left to right.

3, the guide frame 29 (guide member) is disposed so as to substantially coincide with the pulleys 31, 32 in the left-right direction and to be between the pulleys 31, 32 in the front-rear direction. Furthermore, the guide frame 29 is disposed above the pulleys 31, 32 and immediately below the needle plate 101.
As shown in FIG. 7, the guide frame 29 has a bracket portion 295 for fixing it to the inside of the sewing machine bed portion 111, and a cylindrical main body portion 296 for guiding the belts 21 to 24.

The guide frame 29 is disposed directly below the needle plate 101 with the central axis of the main body 296 oriented in the left-right direction.
A fitting groove 297 is formed along the front-rear direction in the left-right center of the upper outer circumferential surface of the main body 296. A plate-shaped pinhole member 30 that is long in the front-rear direction is fixedly fitted into the inside of the fitting groove 297. The pinhole member 30 has a pinhole 13 that penetrates vertically at the needle drop position.
The surface of the needle hole member 30 where the needle hole 13 is formed is flush with or slightly higher than the upper surface of the needle plate 101 .

The main body 296 also slides the belts 21 to 24 in the circumferential direction on the upper part of its outer circumferential surface to feed the sewn material. For this reason, first to fourth guide portions 291, 292, 293, and 294 that guide the first to fourth conveyor belts 21 to 24 are provided on the upper part of the outer circumferential surface of the main body 296.
The first guide portion 291 is provided to the left rear of the needle hole 13, the second guide portion 292 is provided to the left front of the needle hole 13, the third guide portion 293 is provided to the right front of the needle hole 13, and the fourth guide portion 294 is provided to the right rear of the needle hole 13.
Each of the guide portions 291 to 294 is a protruding strip extending in the front-rear direction, and has a width in the left-right direction that is equal to or slightly wider than that of each of the belts 21 to 24. The rear end of each of the guide portions 291 to 294 forms a slope such that the amount of protrusion radially outward from the outer circumferential surface of the main body portion 296 gradually increases toward the front. Also, the front end of each of the guide portions 291 to 294 forms a slope such that the amount of protrusion radially outward from the outer circumferential surface of the main body portion 296 gradually decreases toward the front.

The first guide portion 291 is located to the left of the needle hole 13 and rearward of the center of the needle hole 13 over almost the entire length.
The first guide portion 291 has a flat and horizontal guide surface 291a (patterned portion in FIG. 7 ) forward of the maximum radially outward protrusion of the main body portion 296. The guide surface 291a is disposed so as to face the composite opening 102 of the needle plate 101 when viewed from above.
The guide surface 291 a is set so that the outer surface of the first transport belt 21 that passes over and slides thereon is slightly higher than the upper surface of the needle plate 101 .
The guide surface 291 a is formed such that its front end is located slightly rearward of the center of the needle hole 13 and the first conveyor belt 21 comes into contact with the workpiece rearward of the center of the needle hole 13 .

The second guide portion 292 is located to the left of the needle hole 13 and to the right of the first guide portion 291, and is located forward of the center of the needle hole 13 over almost the entire length.
The second guide portion 292 has a flat and horizontal guide surface 292a (patterned portion in FIG. 7 ) behind the maximum radially outward protrusion of the main body portion 296. The guide surface 292a is disposed so as to face the composite opening 102 of the needle plate 101 when viewed from above.
The guide surface 292 a is set so that the outer surface of the second conveyor belt 22 that passes over and slides thereon is slightly higher than the upper surface of the needle plate 101 .
The guide surface 292 a is formed such that its rear end is located slightly forward of the center of the needle hole 13 and the second conveyor belt 22 comes into contact with the workpiece forward of the center of the needle hole 13 .

The third guide portion 293 is located to the right of the needle hole 13 and forward of the center of the needle hole 13 over almost the entire length.
The third guide portion 293 has a flat and horizontal guide surface 293a (patterned portion in FIG. 7 ) behind the maximum radially outward protrusion of the main body portion 296. The guide surface 293a is disposed so as to face the composite opening 102 of the needle plate 101 when viewed from above.
The guide surface 293 a is set so that the outer surface of the third conveyor belt 23 that passes over and slides thereon is slightly higher than the upper surface of the needle plate 101 .
The guide surface 293 a is formed such that its rear end is located slightly forward of the center of the needle hole 13 and the third conveyor belt 23 comes into contact with the workpiece forward of the center of the needle hole 13 .

The fourth guide portion 294 is located to the right of the needle hole 13 and the third guide portion 293 and rearward of the center of the needle hole 13 over almost the entire length.
The fourth guide portion 294 has a flat and horizontal guide surface 294a (patterned portion in FIG. 7 ) forward of the maximum radially outward protrusion of the body portion 296. The guide surface 294a is disposed so as to face the composite opening 102 of the needle plate 101 when viewed from above.
The guide surface 294 a is set so that the outer surface of the fourth conveyor belt 24 that passes over and slides thereon is slightly higher than the upper surface of the needle plate 101 .
The guide surface 294 a is formed such that its front end is located slightly rearward of the center of the needle hole 13 and the fourth conveyor belt 24 comes into contact with the workpiece rearward of the center of the needle hole 13 .

The guide surfaces 291a, 294a are provided behind the center of the needle hole 13, and the guide surfaces 292a, 293a are provided ahead of the center of the needle hole 13. Therefore, when a speed difference (conveyance difference) is provided between the rear belts 21, 24 and the front belts 22, 23, the belts 21-24 do not interfere with each other, and the conveying force due to the front and rear feed speed difference (conveyance difference) can be applied to the sewn material. Therefore, the desired stitches are formed in the front and rear differential feed, making it possible to improve the sewing quality.

The first pressure mechanism 33 applies tension to all of the belts 21 to 24 that are stretched between the guide frame 29 and the first pulley 31 to prevent slack from occurring.
As shown in FIGS. 2, 3 and 8 , the first pressure mechanism 33 includes a left pressure roller 331 , a right pressure roller 332 , a support plate 333 , and a base block 334 .

The support plate 333 is a long flat plate extending in the front-rear and up-down directions, and is supported by the base block 334 with its longitudinal direction facing diagonally upward and forward.
Furthermore, the support plate 333 supports the left pressure roller 331 and the right pressure roller 332 concentrically and rotatably on the left and right surfaces of the upper end portion thereof. The support plate 333 is disposed so that the left pressure roller 331 and the right pressure roller 332 abut against the outer surface of the belt extending between the guide frame 29 and the first pulley 31 from below at the rear.

The base block 334 is also used in common with the second pressure mechanism 34, which will be described later, and supports the components of the first and second pressure mechanisms 33, 34. The base block 334 is fixedly mounted below the guide frame 29 within the sewing machine bed portion 111.
The support plate 333 has an elongated hole along its longitudinal direction, and is fastened to the base block 334 by two bolts inserted through the elongated holes. The longitudinal direction of the support plate 333 is oriented in a direction substantially perpendicular to the belt stretched around the first pulley 31. Therefore, by loosening the bolts and moving the support plate 333 along the elongated holes, it is possible to adjust the pressure contact force of the left pressure roller 331 and the right pressure roller 332 against the belt. In other words, it is possible to adjust the tension of the belt passing between the guide frame 29 and the first pulley 31.

The left pressure roller 331 and the right pressure roller 332 have the same outer diameter, and are supported by a support plate 333 so as to be rotatable about the same axis along the left-right direction. In addition, the left pressure roller 331 and the right pressure roller 332 each have a width in the left-right direction that is twice or more the width of the belts 21 to 24.
This allows the left pressure roller 331 to come into contact with both the first conveyor belt 21 and the second conveyor belt 22 stretched between the guide frame 29 and the first pulley 31 .
Similarly, the right pressure roller 332 can be brought into contact with either the third conveyor belt 23 or the fourth conveyor belt 24 stretched between the guide frame 29 and the first pulley 31 .

The second pressure mechanism 34 applies tension to all of the belts 21 to 24 that are stretched between the guide frame 29 and the second pulley 32 to prevent slack from occurring.
As shown in FIGS. 2, 3 and 8, the second pressure mechanism 34 has a left pressure roller 341, a right pressure roller 342, a support plate 343, and the above-mentioned base block 334.

The support plate 343 has the same structure as the support plate 333 described above, and is supported by the base block 334 with its longitudinal direction facing diagonally upward and rearward.
The support plate 343 supports the left pressure roller 341 and the right pressure roller 342 concentrically and rotatably on the left and right surfaces of the upper end portion thereof. The support plate 343 is disposed such that the left pressure roller 341 and the right pressure roller 342 abut against the outer surface of the belt extending between the guide frame 29 and the second pulley 32 from above the rear portion.

The support plate 343 also has an elongated hole, and the support plate 343 can be moved along the elongated hole. This makes it possible to adjust the pressure of the left pressure roller 341 and the right pressure roller 342 against the belt stretched over the second pulley 32. Therefore, the tension of the belt passing between the guide frame 29 and the second pulley 32 can be adjusted.

The left pressure roller 341 and the right pressure roller 342 have the same outer diameter, and are supported by a support plate 343 so as to be rotatable about the same axis along the left-right direction. In addition, the left pressure roller 341 and the right pressure roller 342 each have a width in the left-right direction that is twice or more the width of the belts 21 to 24.
This allows the left pressure roller 341 to come into contact with both the first conveyor belt 21 and the second conveyor belt 22 stretched between the guide frame 29 and the second pulley 32 .
Similarly, the right pressure roller 342 can be brought into contact with either the third conveyor belt 23 or the fourth conveyor belt 24 stretched between the guide frame 29 and the second pulley 32 .

The left pressure roller 331 of the first pressure mechanism 33 and the left pressure roller 341 of the second pressure mechanism 34 can both be brought into contact with the first transport belt 21 and the second transport belt 22. Similarly, the right pressure roller 332 of the first pressure mechanism 33 and the right pressure roller 342 of the second pressure mechanism 34 can both be brought into contact with the third transport belt 23 and the fourth transport belt 24.
Therefore, regardless of whether each of the belts 21 to 24 is stretched around the first pulley 31 or the second pulley 32, tension is applied to each of the belts 21 to 24 by either the first pressure mechanism 33 or the second pressure mechanism .

FIG. 8 shows a state in which the second and third conveyor belts 22, 23 fed on the front side of the needle drop position are stretched over a first pulley 31, and the first and fourth conveyor belts 21, 24 fed on the rear side are stretched over a second pulley 32.
FIG. 9 shows a state in which the first and second conveyor belts 21, 22 fed on the left side of the needle drop position are stretched over a first pulley 31, and the third and fourth conveyor belts 23, 24 fed on the right side are stretched over a second pulley 32.

Each of the belts 21 to 24 can be easily removed from each of the pulleys 31 and 32 and replaced by loosening the bolts and retracting each of the pressure rollers 331, 332, 341, and 342.
Therefore, sewing in the hanging state shown in FIG. 8 and sewing in the hanging state shown in FIG. 9 can be easily selected.

For example, in the passing state (front and rear differential feed state) of FIG. 8, it is possible to perform so-called shirring stitches in which the front side of the needle drop position is fed faster than the rear side.
In the front-rear differential feed state, the needle can be fed slower on the front side than on the rear side of the needle drop position to perform sewing with tension applied to the workpiece.

In the crossover state of FIG. 9 (left and right differential feed state), if the left side is fed quickly, a curved stitch that curves to the right can be performed, and if the right side is fed quickly, a curved stitch that curves to the left can be performed.
In addition, since the curvature can be changed according to the difference in speed (difference in conveying amount) between the left and right sides, it is possible to sew a variety of curved lines.

[Sewing machine control system]
FIG. 10 is a block diagram showing a control system of the sewing machine 100.
As shown in the figure, the sewing machine 100 is equipped with a control device 90 that controls the operation of each component. The sewing machine motor 16, the presser motor 73, the first motor 25, and the second motor 26 are connected to the control device 90 via their respective motor drive circuits 16a, 73a, 25a, and 26a.
Encoders 161, 732, 251, 261 for detecting the rotation speed of the sewing machine motor 16, the presser motor 73, the first motor 25, and the second motor 26 are also provided in parallel with the motors 16, 732, 251, 261. These encoders 161, 732, 251, 261 are also connected to the control device 90 via motor drive circuits 16a, 73a, 25a, 26a.

The control device 90 includes a CPU 91, a ROM 92, a RAM 93, and an EEPROM 94 (registered trademark), and executes various operational controls described below.
The ROM 92 stores programs for carrying out various controls, which will be described later.
Various setting data and other programs are also stored in the EEPROM 94. The above-mentioned various setting data and programs may be stored in a non-volatile storage device such as a flash memory, an EPROM, or a HDD, instead of in an EEPROM.

In addition, an operation input unit 96 is connected to the control device 90 via an interface 96a.
The operation input unit 96 includes an input screen 961 on which information required for inputting various settings is displayed.
In addition, the operation input unit 96 can be used to input and set the sewing pitch, the speed difference (difference in conveying amount) between the first motor 25 and the second motor 26, the sewing speed and number of sewing stitches for backtack sewing, the setting value of the pressure applied by the cloth presser mechanism 70 during sewing, etc.
The back tack stitch is a back stitch performed at the start and end of sewing.

The control device 90 is also connected, via an interface 95a, to a pedal 95 that is depressed to start and stop sewing, increase and decrease the sewing speed, perform back tack sewing, etc.

In addition, a height sensor 762 that detects the height of the presser foot 71 is connected to the control device 90 via an interface 762a.

[Pressing Pressure Control]
The CPU 91 of the control device 90 controls the operation of the presser motor 73 so that the pressing pressure reaches the set value set via the operation input unit 96 .
Before sewing starts, the CPU 91 controls the presser motor 73 to lower the presser foot 71 from the upper retracted position toward the workpiece on the needle plate 101. At that time, the height sensor 762 detects the stop of the descent of the presser foot 71 when it reaches the workpiece.
When it is detected that the presser foot 71 has come into contact with the sewing material on the needle plate 101 and stopped descending, the CPU 91 monitors the amount of rotation of the presser motor 73 using the encoder 732. The drive of the presser motor 73 after the presser foot 71 has come into contact with the sewing material is correlated with the amount of compression of the presser spring 75, i.e., the presser pressure by the presser foot 71.
Therefore, the CPU 91 controls the presser motor 73 to rotate up to the rotation amount corresponding to the set value of the presser pressure and then stop the motor.

[Operation control during sewing]
As described above, each of the belts 21 to 24 of the feed mechanism 20 can be selectively stretched around the first pulley 31 and the second pulley 32 .
The operator selects the state in which the belts 21 to 24 are stretched depending on whether front-rear differential feed or left-right differential feed is to be performed.
The front-rear differential feed is a feed in which the workpiece is fed by setting a difference in the feed speed or feed amount between the front belts 22, 23 and the rear belts 21, 24. The front-rear differential feed can perform sewing or shirring by applying tension in the front-rear direction to the workpiece.
The left and right differential feed is a feed in which the workpiece is fed by setting a difference in the feed speed or feed amount between the left belts 21, 22 and the right belts 23, 24. The left and right differential feed makes it possible to perform curved sewing.
That is, the worker performs the work of stretching the belts 21 to 24 in advance so as to achieve either the front-rear differential feed state (FIG. 8) or the left-right differential feed state (FIG. 9) described above.

Furthermore, the operator uses the operation input unit 96 to set the speed difference (conveyance difference, differential feed amount) between the first and second motors 25, 26, which corresponds to the tension of the sewing material, the amount of shirring, or the curvature of the curved stitching.

When sewing is started by depressing the pedal 95, the CPU 91 monitors the amount of depression and drives the sewing machine motor 16 at a sewing speed corresponding to the amount of depression.
At this time, the CPU 91 executes operation control to drive the first and second motors 25, 26 so that the sewing workpiece is fed at a set sewing pitch in a cycle corresponding to the sewing speed. The driving of the first and second motors 25, 26 may be an intermittent feeding operation in a cycle corresponding to the sewing speed, or a continuous feeding operation corresponding to the sewing speed.
Furthermore, the CPU 91 controls the second motor 26 to have a speed or a conveyance amount that is the set stitch pitch minus a set value of the speed difference (conveyance amount difference) between the first and second motors 25, 26. Alternatively, one motor may be driven at a speed that is the set stitch pitch plus 1/2 the set value of the speed difference, and the other motor may be driven at a speed that is the set stitch pitch minus 1/2 the set value of the speed difference.

When the first and second motors 25, 26 are driven to perform intermittent feed operations at a cycle corresponding to the sewing speed, it is preferable that the intermittent feed operation be performed when the sewing needle leaves the workpiece and retreats upward.

[Back tack stitch control]
When a backtack stitch is started, the CPU 91 drives the sewing machine motor 16 at a preset sewing speed for the backtack stitch. The CPU 91 also controls the first and second motors 25, 26 to rotate in the direction opposite to the forward feed at a speed corresponding to the sewing speed. After the backtack stitches are sewn for the set number of stitches, the machine switches to sewing with the forward feed according to the amount of depression of the pedal 95.
When a back tack stitch is input at the end of sewing, the CPU 91 executes the operation control for the back tack stitch in the same manner as described above and then ends sewing.

[Technical Effects of the Embodiments]
The sewing machine 100 has a feed mechanism 20 that feeds the workpiece by means of conveyor belts 21 to 24, and a cloth presser mechanism 70 that presses the workpiece from above.
Therefore, unlike conventional feed dogs, the sewing workpiece held down by the cloth presser mechanism 70 is not struck from below, suppressing vibration and lifting of the sewing workpiece. This allows feeding with high tracking ability to the conveyance of the conveyor belts 21 to 24, and allows stitches to be formed with a highly accurate stitch pitch relative to the set value, improving the sewing quality.
In addition, since the sewing workpiece is not struck from below, the sewing workpiece can be transported properly even if the pressing pressure of the cloth pressing mechanism 70 is reduced. This makes it possible to perform proper sewing even on delicate sewing workpieces or sewing workpieces with low strength.

In addition, the sewing machine 100 does not use a feed mechanism with feed dogs that generates a large inertial force, but instead uses a belt that is easy to reduce in weight, so it is possible to reduce the effects of inertial force during sewing.
In this case, even in the case of sewing at a higher speed where the feed dog cannot maintain the accuracy, it is possible to perform sewing at a more accurate stitch pitch.

In addition, since there is no need for a feed dog that moves horizontally back and forth and a feed mechanism that imparts this movement to the feed dog, it is possible to provide a sewing machine that has less vibration and is quieter.

In addition, even when sewing including sewing with reverse rotation such as back tuck is performed, the sewing pitch can be prevented from being disturbed when switching between forward and reverse. Therefore, it is possible to form overlapping stitches with higher accuracy by preventing misalignment of the forward and reverse stitches, and it is also possible to improve the sewing quality of sewing including back tuck.
Furthermore, the reduction in inertial force enables the sewing machine 100 to quickly start up at high speed rotation, thereby shortening the sewing time and enabling faster sewing.

The sewing machine 100 also uses a presser foot 71 of the presser mechanism 70. There are presser feet with various structures that allow proper sewing depending on the type of sewing and the type of material being sewn. Therefore, the sewing machine 100 can use a wide variety of existing presser feet, and can perform good sewing with high sewing quality for various sewing styles and various materials being sewn.

The feed mechanism 20 of the sewing machine 100 has conveyor belts 21 to 24 which contact the workpiece at the rear and left, front and left, front and right, and rear and right sides of the needle drop position.
This makes it possible to stably perform the target feed, thereby enabling further improvement in the sewing quality.

In the feed mechanism 20, the belts 21 to 24 can be switched around the first and second pulleys 31 and 32 that are rotated and driven individually by the first and second motors 25 and 26. Furthermore, the conveying speed or conveying amount of the first and second motors 25 and 26 can be individually controlled by the control device 90.
Therefore, the sewing machine 100 can selectively perform left-right differential feed sewing or front-rear differential feed sewing of each of the belts 21 to 24. Furthermore, by adjusting the difference in the amount of rotation of the first and second motors 25, 26, it is possible to arbitrarily adjust the magnitude of the difference in the front-rear or left-right differential feed. Therefore, the sewing machine 100 can perform a wide variety of sewing.

The feed mechanism 20 also includes first and second pressure mechanisms 33, 34 that can apply tension to each of the belts 21 to 24. Therefore, whether each of the belts 21 to 24 is looped around the first pulley 31 or the second pulley 32, the conveying operation is excellent. As a result, left-right differential feed sewing and front-rear differential feed sewing can be performed with high precision, making it possible to further improve the sewing quality.

The sewing machine 100 also includes an adjustment mechanism for adjusting the pressure applied by the presser foot 71 to the material being sewn.
As described above, the sewing machine 100 does not use a feed dog, which prevents the presser foot 71 from jumping up, and allows the strength of the pressure applied by the presser foot 71 to be selected over a wide range regardless of the sewing speed.
Therefore, the pressure of the presser foot 71 does not need to be fixed, but can be set to any value by the adjustment mechanism. This makes it possible to sew materials that require low pressure, and enables proper sewing of items made of a wide variety of materials.

[Other configuration examples of the conveyor belt]
Although the sewing machine 100 has been described as having the conveyor belts 21 to 24 that perform feeding at each position relative to the needle hole 13 (needle drop position), the present invention is not limited to this.
11 to 13 are explanatory diagrams showing, in plan view, other examples in which the conveyor belt contacts the sewing workpiece at different positions relative to the needle hole 13 to convey the sewing workpiece. Note that each diagram shows only the portion of the conveyor belt that contacts the sewing workpiece on the needle plate 101, rather than the entire conveyor belt.

11 shows a configuration in which the feed mechanism has two conveyor belts 21A, 22A, which feed the workpiece by contacting the front and rear sides of the needle hole 13. The presser foot applies pressure to the workpiece by contacting the workpiece in a range that includes the range in which the conveyor belts 21A, 22A contact the workpiece (the same applies to FIGS. 12 and 13).
In the case of a sewing machine that uses these two conveyor belts 21A and 22A to feed the sewing workpiece, the belts are conveyed by front and rear motors whose rotation speeds can be controlled separately. The sewing machine is also configured to include a control device that controls the rotation speeds (conveying speed or conveying amount) of the front and rear motors separately.
The front motor and rear motor may utilize the first motor 25 and the second motor 26 in the sewing machine 100 .

In the case of the configuration of FIG. 11 as well, the sewing quality is improved with a highly accurate stitch pitch, and good sewing can be achieved for various types of sewing and various types of materials by using the existing presser foot.
Furthermore, front and rear differential feed can be preferably performed.

FIG. 12 shows a configuration in which the feed mechanism has two conveyor belts 21B and 22B, which feed the workpiece on the left and right sides of the needle hole 13 while being in contact with the workpiece.
In the case of a sewing machine that uses these two conveyor belts 21B, 22B to feed the sewing workpiece, the belts are conveyed by left and right motors whose rotation speeds can be controlled separately. The sewing machine is also configured to include a control device that controls the rotation speeds (conveying speed or conveying amount) of the left and right motors separately.
The left and right motors may utilize the first motor 25 and the second motor 26 in the sewing machine 100 .

In the case of the configuration of FIG. 12 as well, the sewing quality is improved with a highly accurate stitch pitch, and good sewing can be achieved for various types of sewing and various types of materials by using the existing presser foot.
Furthermore, left and right differential feed can be preferably performed.

FIG. 13 shows a configuration in which the feed mechanism has four conveyor belts 21C, 22C, 23C, and 24C, which feed the workpiece by contacting the front, rear, left, and right sides of the needle hole 13.
In the case of a sewing machine that uses these four conveyor belts 21C to 24C to feed the sewing material, the belts are conveyed individually by the front motor, rear motor, left motor, and right motor. The front motor, rear motor, left motor, and right motor all use motors whose rotation speeds can be controlled. The sewing machine is also configured to include a control device that individually controls the rotation speeds (conveyance speed or conveyance amount) of the front motor, rear motor, left motor, and right motor.
The front motor, rear motor, left motor, and right motor may be the same as the first motor 25 and the second motor 26 in the sewing machine 100 .

In the case of the configuration of FIG. 13 as well, the sewing quality is improved with a highly accurate stitch pitch, and good sewing can be achieved for various types of sewing and various types of materials by using the existing presser foot.
Furthermore, it is possible to preferably perform both front-rear differential feed and left-right differential feed. In addition, with this configuration, sewing can be performed by performing left-right differential feed while performing front-rear differential feed.

[others]
Each embodiment of the present invention has been described above. However, the present invention is not limited to the above-mentioned embodiments. For example, in the embodiments, a component integrally formed from a single member may be replaced with a component divided into a plurality of members and connected or fixed to each other. Also, a component formed by connecting a plurality of members may be replaced with a component integrally formed from a single member. In addition, the details shown in the embodiments can be appropriately changed without departing from the spirit of the invention.

In the sewing machine 100, the first and second motors 25 and 26 are used to drive the belts 21 to 24, but the present invention is not limited to this.
For example, the sewing machine may be configured to have a rear left motor, a front left motor, a front right motor, and a rear right motor that individually transport the first to fourth transport belts 21 to 24. In that case, the sewing machine should be configured to include a control device that individually controls the transport speed or transport amount of the four motors.
This provides the same technical effect as the sewing machine 100, and allows for front-to-rear differential feed and left-to-right differential feed to be performed appropriately. Furthermore, in the case of this sewing machine, sewing can be performed in which both front-to-rear differential feed and left-to-right differential feed are performed.

Furthermore, the configuration in which the belt is conveyed while the fabric pressing mechanism 70 presses down the sewing material can be applied to all types of conventional sewing machines in which the sewing material is fed by a feed dog.
For example, the present invention can be applied to a swing needle sewing machine such as a zigzag stitch sewing machine. A swing needle sewing machine can sew pattern stitches such as scallop stitches, which form a repeating pattern by controlling the needle swing width of each stitch. In such pattern stitches, if the sewing speed changes and the sewing pitch error varies, the pattern may become uneven, resulting in a deterioration in sewing quality. However, if a configuration is applied in which the belt is transported while the presser foot 71 holds down the sewing workpiece, the variation in the sewing pitch error caused by the change in sewing speed can be suppressed. Therefore, uniform pattern stitching is possible even if the sewing speed changes, and it is possible to achieve exceptional improvement in the sewing quality of the swing needle sewing machine.

Further, the configuration in which the belt is conveyed while the fabric pressing mechanism 70 presses down the sewing material can also be applied to sewing machines that do not employ differential feed.
For example, the feed mechanism may have one conveyor belt and only one motor as a conveyor drive source.
In the case where a single conveyor belt is used, it is preferable that the conveyor belt contacts the workpiece in the position of either conveyor belt 21A or 22A shown in Fig. 11. It is also preferable that the motor is a stepping motor or the like capable of controlling the number of rotations, and that the motor is provided with a control device for individually controlling the number of rotations (conveyance speed or conveyance amount).

Furthermore, the number of belts may be greater or less, and further, three or more motors may be provided regardless of the number of belts.
For example, the four belts 21 to 24 described above may be driven by three motors. In that case, for example, the front (or rear) two belts are driven by separate motors on the left and right, and the rear (or front) two belts are driven by one motor. This allows the front two belts to perform left-right differential feed, and the front two belts and the rear two belts to perform front-rear differential feed. When performing left-right differential feed, the motor driving the rear two belts may be in an unloaded state.

In the sewing machine 100, the presser mechanism 70 having the presser foot 71 that presses down the workpiece on the needle plate 101 from above has been exemplified as the presser mechanism, but the present invention is not limited to this.
Instead of a configuration having a presser foot 71, the presser mechanism may be an upper feed device in which an upper feed rotating body such as a roller or an endless belt is positioned opposite the feed mechanism 20, and the workpiece is clamped between the upper feed rotating body and the lower feed belt and transported in the sewing direction.
In this case, the presser mechanism may not have a drive source in which the upper feed rotating body, such as a roller or an endless belt, is driven by the conveying force of the feed mechanism 20. The presser mechanism may also have a drive source that imparts a conveying force to the upper feed rotating body, such as a roller or an endless belt. When the presser mechanism also has a conveying drive source, it may be configured to perform differential feeding by providing a difference in conveying speed or conveying amount between the lower feed mechanism and the upper presser mechanism.

11 sewing needle 12 needle bar 13 needle hole (needle drop position)
16 Sewing machine motor 20 Feed mechanism 21 First conveyor belt 22 Second conveyor belt 23 Third conveyor belt 24 Fourth conveyor belt 21A, 22A, 21B, 22B, 21C, 22C, 23C, 24C Conveyor belt 25 First motor 26 Second motor 27, 28 Rotating shaft 29 Guide frame 291, 292, 293, 294 First to fourth guide portions 291a to 294a Guide surface 30 Needle hole member 31 First pulley 311 Left groove 311, 321 Left groove 312, 322 Right groove 32 Second pulley 33 First pressure mechanism 331, 341 Left pressure roller 332, 342 Right pressure roller 333 Support plate 334 Base block 34 Second pressure mechanism 343 Support plate 70 Cloth pressing mechanism (pressing mechanism)
71 presser foot 711 bottom plate 712 connecting portion 73 presser motor 732 encoder 76 detection portion 761 detected object 762 height sensor 90 control device 100 sewing machine 101 needle plate 102 composite opening

Claims (13)

a feed mechanism that feeds the workpiece from below the needle plate by a conveyor belt;
The sewing machine further comprises a presser mechanism for pressing down the workpiece fed by the conveyor belt from above. The sewing machine according to claim 1, characterized in that the feed mechanism uses a single motor as the transport drive source for the transport belt. the feed mechanism includes a plurality of the conveyor belts,
2. The sewing machine according to claim 1, wherein the plurality of conveyor belts include a conveyor belt that contacts the sewn workpiece on the rear and left side of the feed direction relative to the needle drop position, a conveyor belt that contacts the sewn workpiece on the front and left side of the feed direction, a conveyor belt that contacts the sewn workpiece on the front and right side of the feed direction, and a conveyor belt that contacts the sewn workpiece on the rear and right side of the feed direction. The feed mechanism includes:
a first motor and a second motor serving as drive sources for driving the plurality of conveyor belts;
a first pulley that is rotated by the first motor and around which all of the conveyor belts can be stretched;
a second pulley that is rotated by the second motor and around which all of the conveyor belts can be stretched;
having
Each of the plurality of conveyor belts is reversibly wound around each of the first pulley and the second pulley,
4. The sewing machine according to claim 3, further comprising a control device for individually controlling the conveying speed or the conveying amount by the first motor and the second motor. The feed mechanism includes:
a first pressure mechanism capable of applying tension to all of the conveyor belts that can be stretched around the first pulley;
a second pressure mechanism capable of applying tension to all of the conveyor belts that can be stretched around the second pulley;
5. The sewing machine according to claim 4, further comprising: The feed mechanism includes:
a rear left motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the rear and left side in the feed direction;
a front left motor serving as a drive source for a conveyor belt that contacts the workpiece on the front and left side in the feed direction;
a front right motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the front and right side of the feed direction;
a rear right motor serving as a transport drive source for a transport belt that contacts the sewing workpiece on the rear and right side of the feed direction,
4. The sewing machine according to claim 3, further comprising a control device for individually controlling the feed speed or feed amount of each of the rear left motor, the front left motor, the front right motor and the rear right motor. the feed mechanism includes a plurality of the conveyor belts,
2. The sewing machine according to claim 1, wherein the plurality of conveyor belts include a conveyor belt that contacts the sewn workpiece on the front side of the feed direction of the conveyor belt relative to the needle drop position, and a conveyor belt that contacts the sewn workpiece on the rear side of the feed direction. The feed mechanism includes:
a front motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the front side in the feed direction;
a rear motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the rear side in the feed direction,
8. The sewing machine according to claim 7, further comprising a control device for individually controlling the feed speed or feed amount of the front motor and the rear motor. the feed mechanism includes a plurality of the conveyor belts,
2. The sewing machine according to claim 1, wherein the plurality of conveyor belts include a conveyor belt that contacts the workpiece on the left side of a needle drop position and a conveyor belt that contacts the workpiece on the right side of the needle drop position. The feed mechanism includes:
a left motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the left side;
a right motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the right side;
10. The sewing machine according to claim 9, further comprising a control device for individually controlling the conveying speed or the conveying amount by the left motor and the right motor. the feed mechanism includes a plurality of the conveyor belts,
The sewing machine according to claim 1, characterized in that the multiple conveyor belts include a conveyor belt that contacts the sewn workpiece on the front side of the feed direction of the conveyor belt relative to the needle drop position, a conveyor belt that contacts the sewn workpiece on the rear side of the feed direction, a conveyor belt that contacts the sewn workpiece on the left side, and a conveyor belt that contacts the sewn workpiece on the right side. The feed mechanism includes:
a front motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the front side in the feed direction;
a rear motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the rear side in the feed direction;
a left motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the left side;
a right motor serving as a drive source for a conveyor belt that contacts the sewing workpiece on the right side;
12. The sewing machine according to claim 11, further comprising a control device that controls the feed speed or feed amount of the front motor, the rear motor, the left motor, and the right motor individually. The presser mechanism has a presser foot that presses the sewing material from above,
13. The sewing machine according to claim 1, further comprising an adjustment mechanism for adjusting a pressure applied by the presser foot to press down on the material to be sewn.

Images